//2009/08/09 16:12:08
#include <string>
#include <vector>
#include <map>
#include <queue>
#include <algorithm>

using namespace std;

class StairClimb
{
public:
    int stridesTaken(vector <int> flights, int sP)
    {
		int strides = 2 * (flights.size() - 1);
		for(int i=0; i<flights.size(); i++)
		{
			int np = flights[i] / sP;
			if(sP * np < flights[i]) np ++;
			strides += np;
		}
		return strides;
    }
};
